1. Technical Field
The present invention is related to a webbing retracting device for taking up and storing a webbing belt for restricting the body of a vehicle occupant sitting in a seat.
2. Related Art
In webbing retracting devices that configure vehicle seat belt devices there are lock mechanisms provided that restrict rotation of a reel shaft in a pull out direction when a vehicle suddenly decelerates, for example as described in Japanese Patent Application Laid-open (JP-A) No. 05-193441 (Patent Publication 1). A lock gear configuring the lock mechanism described in Patent Publication 1 is coaxially rotatable relative to the reel shaft, and when the reel shaft rotates in the pull out direction relative to the lock gear, coupled to this relative rotation, the teeth of each of a main pawl and a backup pawl mesh with internal teeth formed on both side walls of a frame, and rotation of the reel shaft in the pull out direction is restricted. There are two types of configuration for generating relative rotation between the reel shaft and the lock gear, one being a deceleration detecting means. The deceleration detecting means is provided with an inertial body that moves with inertia when a vehicle suddenly decelerates, and an engaging pawl, pushed up by an inertially moved inertial body, engages with external teeth on the lock gear, thereby restricting rotation of the lock gear, and the lock gear rotates relative to the reel shaft that is rotating in the pull out direction.
Another configuration for generating relative rotation between the reel shaft and the lock gear is another inertial body, separate to the inertial body of the deceleration detection means, provided on the lock gear. This inertial body is connected to the lock gear by a spring, but when the reel shaft together with the lock gear suddenly rotates in the pull out direction, a rotational lag occurs of this inertial body against the biasing force due to the spring and relative to the lock gear. Along with the rotation relative to the lock gear due to the rotational lag, the inertial body moves to the outside in the rotational radial direction of the lock gear, and meshes with inner ratchet teeth that are formed on the inside of a cover, and rotation of the inertial body, and therefore rotation of the lock gear, is stopped. In this manner, by stopping the rotation of the lock gear, the lock gear rotates relative to the reel shaft that is rotating in the pull out direction.
However, just after completion of taking up the webbing belt by the reel shaft if the lock mechanism is unintentionally actuated, then the reel shaft is not able to rotate in the pull out direction from this state, entering a so-called “end-lock state”. In such an end-lock state, since the reel shaft is not able to rotate in the pull out direction, pulling out of the webbing belt becomes difficult. Therefore, in the above Patent Publication 1, when taking up of the webbing belt is competed it is configured such that the external teeth of the lock gear and the engagement pawl of the deceleration detection means do not mesh together, so as to prevent an end-lock state arising.